In recent years large interior panels for automobiles have been molded in one piece out of a homogenous plastic material. These plastic interior panels have the advantage of being of low cost and weight and have a reasonably attractive appearance. However, since they are molded of a homogenous plastic material, they have a somewhat bland and austere appearance which is unsuitable for higher-price luxury automobiles. For use in luxury automobiles, trim features such as padded trim pieces are added to the molded interior panels to provide a luxurious appearance and feel. Padded trim pieces are made generally of a relatively rigid support member comprised of pressboard or the like, a foam pad and a vinyl covering for the foam.
In a known method of making padded trim pieces, the vinyl covering is wrapped around the edges of the trim piece and secured to the inside of the support member by gluing. Since the vinyl is wrapped about the edges of the trim piece, however, the vinyl tends to bunch at the corners of the trim piece. This bunching, of course, is unsightly. More importantly, this bunching results in an increased material thickness at the corners of the trim piece. Consequently, when the trim piece is mounted to the interior panel, the bunched material prevents a close mating between the edges of the trim piece intermediate the corners and the interior panel, resulting in unsightly gaps between the intermediate edges and the interior panel. Such unsightly gaps are, of course, antagonistic to a luxurious appearance. Also, gaps act as dirt traps and make cleaning difficult.
The present invention provides an improved interior trim piece consisting of a relatively rigid support member such as pressboard or the like, a foam or fibrous pad, and a vinyl or cloth cover which is secured to the support member in a fashion to avoid bunching at the corners of the trim piece. In accordance with this invention, the cover and the foam pad are constructed in a manner so that the edges of the trim piece mate nearly perfectly with the interior trim panel to provide a very attractive finished appearance with no gaps between the edges of the trim piece and the interior trim panel. In addition, this invention provides a trim piece which is capable of standing up to normal abuse without separation of the cover, pad and support member.
The improved trim piece of this invention is manufactured by a novel bonding method that utilized dielectric, ultrasonic, or any other suitable bonding process, wherein the upper and lower surfaces of the bonding die form an acute angle proximate the edge of the trim piece and wherein said acute angle is obliquely disposed with respect to the motion of the upper and lower surfaces of the bonding die. The acute angle causes die convergence near the edge of the trim piece to provide a very secure bond between the cover, the pad, and the support member adjacent the edges of the trim piece. Because of the secure bond, the cover can be trimmed in a fashion which provides optimum mating with the interior panel to provide a finished appearance.
Other features and advantages of this invention will be apparent from the following description of the invention.